Conduit fitting



R. P. DUNMIRE CONDUIT FITTING Filed Oct. 30. 1925.

May 8, 1928.

W TOR A TTORNEYS.

Patented May 8, 1928.

UNITED s'rA'rasl RUSSELL P. DUNH IBE, OF ERIE, PENNSYLVNIA, .ASSIGNOR T0 ERIE HALLEABLE PATENT OFFICE.

IRON COMPANY, OF EBIE, PENNSYLVANIA, 'A CORPOBA'I'IOH OF PENNSYLVNI.

COND'UIT IITTING.

;Application led October 80, 1925. Serial 170.` 85,8%.V

This invention is designed to provide means forz securing threadless conduits to conduit boxes, commonly called knock-out boxes, that is, boxes having openings with closures sueh`that they may be readily removed by slight force. These boxes are usuall of comparatively thin wall and it is desirable to adapt a. means of securing a I threadess conduit to suchiwall using a means hereto ore designed for use with the ordinary conduit boxes or tittings. Features and details of the invention will appear from the specification and claims.

The invention is illustrated in the accompanying drawings as follows:-

Fig. 1 shows a knock-out box in' section on the line 1-1 in Fig. 2.

Fig. 2 a section on the line 2-2 in Fg. 1. Figi 3 a sectionon the line 3-3 in Fig; 2.

Fig. 4; a side elevation of the contractible sleeve.

Fig. 5 a perspctive view of the re-enforeing plate.

1 marks the box, 2 the opening in the box, and 3 a reinforeing plate having an opening 4 registering with the opening in the box, this opening having preferably tapered walls and flat portions or portions out of round 5.

The contractible sleeve 6 is one, as before lncntioned,` heretofore designed for use in.

ordinary conduit boxes. It has a longitudinal slit 7.openin into a circumferential slit 8 and is provide with a guard 9 at its inner end forming a stop guard for the end of a'u inserted conduit A. The sleeve has the tapered outer Wall 10 with flats, or portions out of round 11 correspondingto the shape of the parts 5. The contractible sleeve is provided with a screw-thread 12 at its outer end.

The contractible sleeve is inserted through a re-enforcing` plate through the opening 2. A nut 13 is screwed on to the sleeve. The nut has a spacer 14 as shown integral with the nut and is arranged between the nut and the wall of the' box and thus aflords a means by which the nut may exert axial movement on the sleeve to draw it into the openings and thus through the Wedging action of the taperedportion contract it into clamping engagement Withl a conduit.

In the lower part ofl the box I have shown an alternative construction in which the vsleeve 6 operates with' an opening 'in the box alone, this opening. in the box having fiats 2** for engaging the similar portions of the sleeve. A nut 15 is provided for this sleeve with a spacer 16.

What I claim as new is 1. In a conduit fitting,` the combination of a conduit box having a conduit opening in its wall; a re-enforcing plate having an opening registering With the opening in the box; a slotted contractible sleeve in the openings in the plate and box having a tapered outer Wall adapted to engage the wall of the plate to contract the tapered sleeve upon .endwise movement and a screw-threaded outer end; and' a nut on the screw-threaded outer end exerting pressureon the wall to move the sleeve to contract the same.

2. In a conduit fitting, the combination of a conduit box having a conduit opening in its Wall; a re-enforcing plate having an opening therein in register with the opening in the wall, said plate having a part engaging the wall of the box looking the same against turning relatively to the box and said opening having `a portion therein out of round; a slotted contraetible sleeve in the. opening having a tapered outer wall adapted to engage the wall of the re-enforcing` plate to contract the sameupon endwise my hand.

EUSSELL P. DUNMIRE. 

